Part IV: Exercises

Briefly explain the two important pieces of information that we can gather from the identity principle.

For statements 1-4, explain how the identity principle comes into play.

Eg. “Soda” and “pop” are equivalent terms. 

Answer: The referents of the terms “soda” and “pop” share all the same characteristics. By the identity principle, we know that two terms whose referents have all the same characteristics must be equivalent. 

1. “Bike” and “scooter” are not equivalent terms.
2. “Tennis shoes” means the same thing as “sneakers.”
3. A lawyer is someone who has the authority to interpret the law.
4. One should not compare apples and oranges.

Match each of the following terms with a term in the column that satisfies the identity principle.

For phrases 1-5, come up with a term that satisfies the identity principle (i.e. come up with a term whose referent satisfies all the criteria of the given phrase).

Eg. A device used to make calls

Answer: phone

1. The star closest to Earth
2. The fourth planet from the Sun
3. The first president of the United States
4. The largest country in the world 
5. Plato’s most famous student (hint: he founded the type of logic you’re learning)

Challenge! Consider the example of equivocation below. Can you explain how it violates the identity principle? (hint: focus on the term in the asterisks)

Angela is *hip.*

*Hips* don’t lie!

Therefore, Angela doesn’t lie.